This invention relates to the manufacture of components for inflatable restraining systems used in automotive vehicles, and more particularly to an apparatus for charging metallic canisters used in such systems with a gas under high pressures and sealing such canisters while maintaining them under pressure.
In the prior art, there has been developed an apparatus for pressurizing metallic canisters used in inflatable restraining systems for automotive vehicles by injecting a gas under pressure through a filler opening provided in the canister and then sealing such filler opening while continuing to supply pressurized gas to the canister. Generally, such apparatus is provided with a member engageable in sealing relation with a canister being charged, having a guide passageway communicable with the filler opening of the canister. Such member can be either stationary with means for displacing the canister into sealing engagement with the member or displaceable with means for displacing the member into sealing engagement with the canister. In either of such arrangements, with the member disposed in sealing engagement with the canister and the guide passageway of the member communicating with the filler opening in the canister, means are provided for injecting an inert gas under pressure through the guide passageway in the sealing member and the filler opening in the canister to pressurize the canister, delivering a welding ball through the guide passageway of the sealing member so that it deposits on the canister across the filler opening therein and for extending a welding rod through the guide passageway in the sealing member to positively engage and fuse the welding ball and close the filler opening while continuing to maintain the canister under pressure. An example of such type of apparatus is described and claimed in U.S. Pat. No. 5,352,860.
Canisters intended to be pressurized by such type of apparatus often vary in configuration, wall thickness, filler opening size and charging pressure requirement. Accordingly, for such an apparatus to be effective and productive, it must be capable of pressurizing such canisters at pressures in the range of 3,500 to 10,500 psi, positively maintaining a seal between the sealing member and the canister to accommodate such high pressures, reliably delivering welding balls of different sizes to accommodate canister filler openings of different sizes, and effectively preventing leakage of gas, particularly through the welding ball feeding mechanism.
It thus has been found to be desirable to provide an apparatus of the type described which is capable of not only providing an effective seal between the sealing member and the canister and pressurizing the canister while maintaining such seal but of reliably feeding welding balls of different sizes to accommodate canisters of different filler hole sizes.